Introduction Osteoporosis is common in Crohn’s disease patients.1 Autophagy genes have so far never being studied as potential risk factors for osteoporosis in Crohn›s disease.
Methods We have analysed the risk for osteoporosis among Crohn’s disease patients expressing the rs2241880 polymorphism of the ATG16L1 gene. Patients diagnosed with Crohn’s disase through histological, radiological and endoscopic findings were recruited. A blood sample for genotyping was taken and a DEXA Bone Density scan was performed in each patient. Genotyping for this variant involved:
– DNA extraction
– Gradient Polymerase Chain Reaction (PCR)
– Quantitative PCR and High Resolution Melt (HRM)
– Restriction Fragment Length Polymorphism (RFLP) of PCR product
Results 83 Crohn’s patients were included in the study. Following genotyping, 33 patients were found to have no mutation (wild type), 44 were heterozygous and 6 were homozygous for the rs2241880 variant of the ATG16L1 gene. The table below shows the mean T and Z scores at the hip and spine of patients with the wild type, heterozygous and homozygous variants.
Patients Homozygous for the rs2241880 variant had lower mean T and Z scores at the hip than those Heterozygous or Wild Type. Using t-test, there was no statistical difference between the Homozygous, Heterozygous and Wild Type patients’ hip T scores (p:0.314), Z scores (p:0.441), and spine T scores (p:0.751) and Z scores (p:0.822). Using χ2 test, the relationship between the 3 different variants (homozygous, heterozygous and wild type) and the risk of osteoporosis (T score < –2.5), osteopoenia (T score: –1.0 to –2.5) and normal (Tscore > –1.0) was not statistically significant (p:0.978).
Conclusion We found no significant difference between the T and Z scores of patients with ATG16L1 Homozygous, Heterozygous and Wild Type alleles. However, there is a trend in the mean T and Z scores at the hip with lower scores in patients with Heterozygous/Homozygous alleles. Such a trend is not present in the spine. While the authors can offer no explanation for this difference, studies on larger populations are needed to better investigate the relationship between ATG16L1 mutations and the risk of osteoporosis.
Disclosure of Interest None Declared.
Lewis NR, Scott BB. British Society Guidelines for osteoporosis in inflammatory bowel disease and celiac diseas. BSG guidelines in Gastroenterology. June 2007; 1–12.
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